<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Mon, May 2, 2016 at 1:17 PM, Hal Finkel <span dir="ltr"><<a href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span>----- Original Message -----<br>
> From: "David Blaikie" <<a href="mailto:dblaikie@gmail.com" target="_blank">dblaikie@gmail.com</a>><br>
> To: <a href="mailto:reviews%2BD19708%2Bpublic%2Be9ddc425037326c5@reviews.llvm.org" target="_blank">reviews+D19708+public+e9ddc425037326c5@reviews.llvm.org</a>, "Hal Finkel" <<a href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>><br>
> Cc: "Richard Smith" <<a href="mailto:richard@metafoo.co.uk" target="_blank">richard@metafoo.co.uk</a>>, "Adrian Prantl" <<a href="mailto:aprantl@apple.com" target="_blank">aprantl@apple.com</a>>, "Duncan P. N. Exon Smith"<br>
> <<a href="mailto:dexonsmith@apple.com" target="_blank">dexonsmith@apple.com</a>>, "Eric Christopher" <<a href="mailto:echristo@gmail.com" target="_blank">echristo@gmail.com</a>>, "Jun Bum Lim" <<a href="mailto:junbuml@codeaurora.org" target="_blank">junbuml@codeaurora.org</a>>,<br>
> "cfe-commits" <<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>><br>
> Sent: Friday, April 29, 2016 4:52:26 PM<br>
> Subject: Re: [PATCH] D19708: [CGDebugInfo] Generate debug info for member calls in the context of the callee<br>
> expression<br>
><br>
><br>
> You could simplify the test case further, down to just:<br>
><br>
> struct foo { void bar(); };<br>
> void f(foo *f) {<br>
> f->bar();<br>
> }<br>
><br>
> and check that the call instruction has the desired column (or if you<br>
> want a test that doesn't depend on column info (you can force it on<br>
> with a flag, but we might vary whether it's on by default based on<br>
> target, etc, I'm not sure) you could put 'bar();' on a separate line<br>
> from 'f->' and check the call was on the second line and not the<br>
> first).<br>
<br>
</span>Certainly. I'm not sure much we want to reduce the test case, however, because I particularly want to cover the case of two calls on the same line with column info.</blockquote><div><br></div><div>Why is it helpful to cover two calls? That's certainly where the issue was observed, but it's not the bug/fix as such. Once we put the location at the start of the function name we incidentally improve the situation where there are two calls.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Given that this is still pretty simple, I think that covering it directly seems reasonable.<br></blockquote><div><br></div><div>I think it can make tests more confusing when it comes to tracking the actual behavior change/intent of the test, etc.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span>> Richard might be able to tell us whether there's a preferred place<br>
> for a test for a change like this - should it be a debug info test,<br>
> a diagnostic test,<br>
<br>
</span>At least for the test you suggested in a previous e-mail, this patch has no effect on the output diagnostics (although it certainly does have the desired effect on the debug info). Specifically, even with this patch, we still have:<br>
<br>
$ cat /tmp/loc.cpp<br>
<span> struct foo {<br>
const foo *x() const;<br>
void y();<br>
};<br>
<br>
void f(const foo *g) {<br>
g->x()->y();<br>
g->x()->x()->y();<br>
}<br>
<br>
</span>$ clang /tmp/loc.cpp -fsyntax-only<br>
/tmp/loc.cpp:7:3: error: member function 'y' not viable: 'this' argument has type 'const foo', but function is not marked const<br>
g->x()->y();<br>
^~~~~~<br>
/tmp/loc.cpp:3:8: note: 'y' declared here<br>
void y();<br>
^<br>
/tmp/loc.cpp:8:3: error: member function 'y' not viable: 'this' argument has type 'const foo', but function is not marked const<br>
<span> g->x()->x()->y();<br>
^~~~~~~~~~~<br>
</span> /tmp/loc.cpp:3:8: note: 'y' declared here<br>
void y();<br>
^<br>
2 errors generated.<br></blockquote><div><br></div><div>Curious - perhaps we should fix the diagnostic too? I guess it's using the start location instead of the preferred location?<br><br>Hmm, yeah, maybe that's not right anyway - it's specifically trying to describe the left operand, though that's different from any case where a normal operand is mismatched by constness. Then it just says it can't call the function & points to the function (with a note explaining)<br><br>Anyway - seems OK. Please commit.<br><br>- David</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Thanks again,<br>
Hal<br>
<div><div><br>
> or perhaps just an ast dump test?<br>
><br>
> Perhaps a test for the case where there is no valid callee would be<br>
> good? Where does that come up - call through a member function<br>
> pointer?<br>
><br>
><br>
> On Fri, Apr 29, 2016 at 9:19 AM, Hal Finkel via cfe-commits <<br>
> <a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a> > wrote:<br>
><br>
><br>
> hfinkel updated this revision to Diff 55610.<br>
> hfinkel added a comment.<br>
><br>
> Use David's suggested approach: Modify the preferred expression<br>
> location for member calls. If the callee has a valid location (not<br>
> all do), then use that. Otherwise, fall back to the starting<br>
> location. This seems to cleanly fix the debug-info problem.<br>
><br>
><br>
> <a href="http://reviews.llvm.org/D19708" rel="noreferrer" target="_blank">http://reviews.llvm.org/D19708</a><br>
><br>
> Files:<br>
> include/clang/AST/ExprCXX.h<br>
><br>
><br>
> test/CodeGenCXX/debug-info-member-call.cpp<br>
><br>
> Index: test/CodeGenCXX/debug-info-member-call.cpp<br>
> ===================================================================<br>
> --- /dev/null<br>
> +++ test/CodeGenCXX/debug-info-member-call.cpp<br>
> @@ -0,0 +1,24 @@<br>
> +// RUN: %clang_cc1 -triple x86_64-unknown_unknown -emit-llvm<br>
> -debug-info-kind=standalone -dwarf-column-info %s -o - | FileCheck<br>
> %s<br>
> +void ext();<br>
> +<br>
> +struct Bar {<br>
> + void bar() { ext(); }<br>
> +};<br>
> +<br>
> +struct Foo {<br>
> + Bar *b;<br>
> +<br>
> + Bar *foo() { return b; }<br>
> +};<br>
> +<br>
> +void test(Foo *f) {<br>
> + f->foo()->bar();<br>
> +}<br>
> +<br>
> +// CHECK-LABEL: @_Z4testP3Foo<br>
> +// CHECK: call {{.*}} @_ZN3Foo3fooEv{{.*}}, !dbg ![[CALL1LOC:.*]]<br>
> +// CHECK: call void @_ZN3Bar3barEv{{.*}}, !dbg ![[CALL2LOC:.*]]<br>
> +<br>
> +// CHECK: ![[CALL1LOC]] = !DILocation(line: [[LINE:[0-9]+]], column:<br>
> 6,<br>
> +// CHECK: ![[CALL2LOC]] = !DILocation(line: [[LINE]], column: 13,<br>
> +<br>
> Index: include/clang/AST/ExprCXX.h<br>
> ===================================================================<br>
> --- include/clang/AST/ExprCXX.h<br>
> +++ include/clang/AST/ExprCXX.h<br>
> @@ -145,6 +145,14 @@<br>
> /// FIXME: Returns 0 for member pointer call exprs.<br>
> CXXRecordDecl *getRecordDecl() const;<br>
><br>
> + SourceLocation getExprLoc() const LLVM_READONLY {<br>
> + SourceLocation CLoc = getCallee()->getExprLoc();<br>
> + if (CLoc.isValid())<br>
> + return CLoc;<br>
> +<br>
> + return getLocStart();<br>
> + }<br>
> +<br>
> static bool classof(const Stmt *T) {<br>
> return T->getStmtClass() == CXXMemberCallExprClass;<br>
> }<br>
><br>
><br>
><br>
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><br>
><br>
><br>
<br>
</div></div><span><font color="#888888">--<br>
Hal Finkel<br>
Assistant Computational Scientist<br>
Leadership Computing Facility<br>
Argonne National Laboratory<br>
</font></span></blockquote></div><br></div></div>